弹性分组环中MAC协议公平性研究-电路与系统专业论文.docxVIP

Abst Abstract II万方数据 II 万方数据 Abstract As a new network structure and data transport technology,the resilient packet ring(RPR) can overcome the drawbacks of the previous technology choices for MAN ring such as the SDH ring and the Gigabit Ethernet ring.RPR also adopts the dual-ring topology,spatial reuse, topology self-discovery,protect rotate and statistic multiplex etc,which enables it the ability to achieve the robust,high efficiency and economic simultaneously,and RPR has become the primary technology in metropolitan area networks.The IEEE 802.17 workgroup has complete the standard framework for RPR,however,many key technologies about RPR are in need of being further researched and discussed,one of which is the fairness of MAC protocol.How to allocate the ring bandwidth fairly as well as efficiently is an important issue in RPR networks and MAC protocol fair algorithms take the charge of such issue. However,there exist some questions in current fairness algorithms.Designing a proper fairness algorithm for RPR to dynamically achieve these properties is the main objective of the paper. Firstly ,we introduced the background knowledge of RPR, including the technique characteristics, the reference model and the frame structure of RPR,and analyzed RPR’s key techniques in detail. Then,we introduced the background of MAC protocol fairness in RPR, discussed basic fairness scheme and fairness rules.We stressly introduced some MAC protocol fairness algorithms in RPR and gave out the disadvantages of current fairness algorithms. Subsequently,we generalized RIAS fairness rule,namely GRIAS(Generalized Ring Ingress Agreggated with Spatial Reuse) fairness.Based on the rule,a new high performance fairness algorithm(HP-fa) is introduced to overcome the disadvantages of current fairness algorithms.Through simulation,we analyzed the performance of the new algorithm,the result showed the new algorithm had better performance than current fairness algorithms. Lastly,we concluded this p